Classic & Vintage - bike fit: new vs old theories?
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11-19-07, 06:04 PM
I recently bought a new steel Bianchi as my first road bike, and I'm really enjoying it. I went to a guy who was very serious about measuring, and I'm busy trying to get used to the new position.
It seems to me that when I was riding my Gitane (I never claimed I wasn't a cliche) back in the 70s I was much more strapped on to a larger frame; it was a little scary, but I really felt like my whole body, or at least all of my legs, was (were?) involved in pedalling.
So I'm wondering if the theory of bike fit and bike build has changed over time. And, more to the point, if I follow through with my plan of picking up a vintage bike for the fun of it, do I try for the same measurements as my new Bianchi, or do I for that more stretched out feeling?
11-19-07, 06:31 PM
On the racing bikes the geometry has definitely changed. I raced back in the early to mid 70's and we preferred the more stretched out feeling. I know when tri-racing came along the tri riders moved the saddles way up to give them more of a "running on the pedals" posture. I could never get comfortable on that style of bike. By today's standards most of my racing bikes from the 70's have fairly slack angles and the saddle is set too far back. One thing I cannot get used to is the "compact" geometry of today's bikes with the sloping top tube. Also depending on the model of your Gitane it may have been more of a sport geometry rather than a racing geometry.
I don't know if the theory of bike fit has changed since the 1970's ... but my 49-year-old body sure as shootin' fits a bike different than the 19-year-old model did.
11-19-07, 08:49 PM
Trend now is to ride a bike that's 4-5cm smaller than what we would have ridden back in 70's. A 59 then/54 now. I am soooo tired of seeing 6 ft tall 40 year old men in full kit on 54cm bikes with a seat post sticking way up in the stratosphere and hardly any height from bars to top tube. They ain't never gonna ride the TdF so why don't they just buy something comfy to ride.
11-19-07, 08:59 PM
Back in the early 70's we'd set you up at the shop a little differently than is done today. First off, anything under $150.00 was usually in four sizes: 19-1/2", 21-1/2", 23-1/2", 25-1/2" (Schwinn: 20, 22, 24). Once you got over that price point, the sizes in between would appear. You'd set the seat height so it was 105-110% of your heel reach to the pedal on the down stroke, and once the seat was set your hand was supposed to cover the exposed seat tube.
One of my biggest shocks in getting back into the sport is how small a frame they expect someone to ride nowdays. And I absolutely cannot get used to sloping top tubes and whatever a compact frame is supposed to be.
Guess I'm going to have to look for a cheap Schwinn Fastback and see if I can learn to like the modern styles.
11-19-07, 09:03 PM
Yes, the theory of bike fit has changed. Taller frames were the norm back in the day which worked out well with the normal "7" shaped stems of the time to give an appropriate amount of drop from seat to bars. If you could clear the top tube while standing over the bike you should have about "fist" full of seatpost showing and a 2-3" drop from seat to bars. Modern frames, even those with horizontal top tubes, are generally sized a couple of centimeters smaller. Modern threadless stems have rise that evens out the seat to bar drop. Six or one, half dozen of the other. However, that doesn't necessarily corrolate directly to geometry. I have a 2002 Bianchi Veloce. The geometry is quite similar to my 1972 Bottecchia and they feel very similar on the road. What is different is that the Bianchi, which was fitted according to modern fit, is a 55cm C-C frame while the Bottecchia is a 58.5. The Bottecchia has a 1cm longer top tube while the Bianchi has a 1cm longer stem so the riding position is the same. I suppose that could have some affect on weight distribution but I can't tell any differance. Depending on the particular older bike you are considering, many came in 2 inch increments so you might find that if you get a frame sized according to the modern theory that the top tube is a bit short. But I have short legs and a very long torso. YMMV. For the 72 Bottecchia I went with the same size (23") I rode back then. I plan someday to get a late 80's - early 90's Bottecchia frame and build it up with modern kit. For that bike I'll probably go a little smaller like 56cm.
11-19-07, 10:20 PM
Bike sizing can get pretty complicated. I came to believe I needed a 54cm frame when I sat on a 57cm '70s road bike, I didnt really take into account the 27" wheels and the huge tire clearance. I couldnt stand over the top tube. Now if I sat on a real 57cm bike from the 1970s it woulda fit beautifully.. or at least very close with the 700c tires and tighter wheel clearance, if that happened I wouldnt of bought a too small for me frame which I cant do anything with, damn you crappy bike boom bikes!!
And I also agree with what is the current norm looks stupid, the 10 miles of seat post coming out, the sloping frames (which doesnt help with the mile high seat posts), not to mention all the headset spacers people wind up putting on their bike to get it comfy, looks really stupid.
GIOS made a "compact" frame which I would love to get, it doesnt have a stupid sloping top tube, a 56c-c seat tube and a 54 top tube, perfect for me. (I would have to use a 120 length stem with it, which I like for asthetic reasons).'
11-19-07, 10:55 PM
If I'm not mistaken, aren't some of Cannondale's models from a few years ago sized traditionally? I can't recall a single full-fledge road machine in their '04 catalog without a straight top tube.
11-20-07, 03:51 PM
My Raleigh frames from the 1980s are 23 1/2" (60cm) and they are spot-on the right size. Now, when I comw to look at say, Focus' frame sizes, 60cm is XXXXXXXXXXXXXXL! It seems as though 54-56cm is my size although as with so many cycles, these are mail order so I'm stuffed if I can see whether one fits before I shell out hundreds. Hmmm.
11-20-07, 06:22 PM
+1 to all the above, Expectations of what a comfortable fit has changed also, with the bars being much lower today than in the past. Look at old racer photos, and you see the bars are about 1 - 2 inches below the top of the saddle. riders rode more poor roads back then and were on the bike longer so they sacrificed aerodynamics for comfort. Today, its more about being as aerodynamic as possible and training your body to be comfortable on a bike set up to be aero. Me, as a bona-fide old fart, I still go for comfort, so as a long legged 5'11" er, I ride a 62 cm bike and could happily go larger.
11-20-07, 06:55 PM
Look at old racer photos, and you see the bars are about 1 - 2 inches below the top of the saddle. riders rode more poor roads back then and were on the bike longer so they sacrificed aerodynamics for comfort.
Depending on the decade, acers rode in the "hooks" typically, as comfortable brake levers to differently were not around.
I suspect the 'new' sizing has more to do with production of modern frames that advances in fit and 'technology'.
It's a lot cheaper to have fewer sizes per model than to have increments of size to better fit an individual buyer. Especially the cost to tool molds for carbon fiber bikes.
But as it was mentioned above, longer seatposts and lengthened rise of stems can't substitute for geometry of the frame and fork. I noticed more bikes with what was considered very lazy head tube angles these days. Maybe an attempt to push the front wheel out of the way of long legged riders with long cranks.
I think it's more of a top-down marketing push to size folks to the 'compact' frames.
In one thread, two posters argued away of the correct stem/bar to seat height aspect of a race frame.
An obviously younger rider argued away that a road frame is designed to be set up for the high seat, low stem riding position. And attempting to ride it in any other configuration is wrong, unsafe and irresponsible of any shop who would allow a rider to have a stem/seat level riding position.
Quite hilarious to read, but he truly believed in what he stated like it was a religious faith.
11-21-07, 06:51 AM
Back in the late 60s/early 70s I rode my track bikes on the road, for 30 to 50 miles each day, with hands necessarily in the drops all the time. But, even though I was on a dedicated track racing bike, my saddle height was far closer to the stem height level than is the norm today on any road bike. _ I always laugh when I see modern "fixies" set up with the saddle easily 12 to 15 inches above the drops and hear the owner boasting how comfortable the ride is. He must be riding only a block to the local Starbucks to be "seen" looking fashionable (or to the chiropractor).
I absolutely hate the ill-fitting look of modern compact frames which are certainly no better a fit for any rider than a tuxedo would be if sold in sm-med-lg sizing. To me they look like someone is trying to fit into their little brother's bike by adding on an enormous seatpost. Circus clowns on tiny bicycles come to mind. I think these "compact" road frames are now more easily marketed to younger riders - ones who became used to riding small framed freestyle bikes... and then continued riding them for 10 years too long because they saw morons on TV looking cool by crashing their bikes off of roofs. It is much cheaper and more profitable to make an absolute minimum variety of sizes, and convince consumers they fit, and now there is an entire generation who knows no better to begin with. _ And, if I were a Pro racer, you could pay me a 6 or 7 digit salery to ride wearing a ballerina's tutu and I wouldn't care. So seeing what the Pros currently ride means nothing to me. They're paid for their pain.
Beyond compact frames, ... A few years back I stupidly bought a Cannondale road bike. The size was 56 cm. The length was still too long even with a shop-installed stem an inch shorter in length. The saddle was set unnaturally high (to my mind, that is) and the stem could not be raised to approximate a comfortable position. If I had selected a 60cm bike, the saddle could have been lower, thus making the stem effectively higher... but this would have lengthened the already too long frame a few more inches! So, it was a no win situation. I probably looked suitably "aero" [therefore I must be fitted correctly, right?] but after riding in pure pain inspite of frequent attempts by the shop to modify the bike to better suit my requirements, I just gave up and bought a vintage bike of a larger size but which I could still easily stand over, and with more familiar traditional geometry than the newer "Gee, can you make me look like a real racer-boy?" type styling, and I quickly rekindled my long lost love of cycling.
I think bike "design" is now about weight savings which can easily be marketed along with the latest "even-lighter-this-year" components, ... about helping you to simply "Look" like you can ride - along with your latest pro-team fashions in shiny spandex, which also makes money, ... and about selling Fashion-Correct sleek bike designs which few riders are expected to use much and will soon trade in for the next trendy new model anyway.
The more "serious" riders and amateur racers around here are typically riding outdated bikes which are built up with "updated" components which are also at least 10 years old. And the MOST serious (and still competitive) riders I know are still riding bikes they bought 20 years ago when they were racing Junior Classification and Greg Lemond was winning the TDF, and they are still perfectly content using later upgraded 8-speed STI or ERGO components from the early 90s.
But, please, feel free to just color me "retro-grouch" red. :mad: And, by all means spend $6,000 on your new bike... and do the same next year, too. _ It keeps my local bike shop profitable and ensures job security for my mechanic friends.
Can't comment on the evolution of bike fit since I'm too young but will agree that bars close to saddle level is much more comfortable, and that sloping TTs are ugly.
However, my favorite "fitting" trick (from a bike book) is the following and I don't get how it can work. "The combined top tube and stem length should position the bars so that in normal riding position the front hub is blocked from view by the bars" ...
I've read that 'fitting trick' too way back in the 80s. A problem arises when the fork blades vary. A touring bike is going to have the hub further out.
11-21-07, 08:28 AM
In general, that fitting trick works very well for me - just about everything I've got in the garage, other than my mountain/hybrid-based flat bar bikes are set up that way. I've gotten to the point that said fit is my starting point for long-term sizing a bike.
Forum regulars have seen my ca. 1960 racing photos of noted Austrian racer Adolf Christian and others on what today would be unfashionably tall frames.
I generally very strongly consider 55cm C-T to be my ideal size in a traditional road frame, but I was able to ride a 58.5cm C-T Nishiki Competition for 20 years because it had a low bottom bracket and a short top tube. I had to give up on my otherwise highly satisfying 58cm 1980 Peugeot PKN-10 because the top tube was simply too long and too high off the ground for my own comfort. A minimum-reach stem did help, but it looked horrible, in my opinion.
Since my Bianchi has a long-reach stem and since my fingertips fall short of the handlebar with my left elbow against the nose of the saddle (the situation is at least 1 cm worse on the right), I am tempted to try a shorter-reach stem, to see whether it makes me feel more secure while shifting, signalling, or otherwise riding with only one hand on the bars.
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